1. Technical Field
The present invention generally relates to a pixel driving circuit, a pixel driving method and a light emitting display device and, particularly to a pixel driving circuit, a pixel driving method and a light emitting display device capable of compensating threshold voltage variations of a driving transistor and a light emitting diode (LED) in each pixel.
2. Description of the Related Art
Display devices are one of the most important man-machine interfaces in many modern electronic systems. Moreover, light emitting display devices whose pixels are constructed with LEDs (e.g., organic LEDs) have become one of the development mainstreams of the modern display device/panel technology.
The light emitting display devices are generally classified into passive type and active type display devices, while the characteristic of the active type display devices are better than that of the passive type display devices. In each pixel of an active type display device, besides that a LED is provided for emitting light to display images, at least one driving transistor (e.g., a thin film transistor) is provided for supplying a driving current to the LED for driving the LED to emit light. The driving current is relevant with a threshold voltage of the driving transistor, and the driven extent/degree of the LED is relevant with a threshold voltage of the LED.
In the application environment of modern manufacturing technology and the light emitting display device, as to the driving transistors of different pixels belonging to a same light emitting display device, threshold voltages of the driving transistors of the different pixels would occur drift variations along with the increase of working time, so that the brightness of the light emitting display device is uneven and thereby affecting the display quality of the light emitting display device. In addition, as to the LEDs of the different pixels, threshold voltages thereof may occur drift variations along with aging, which would result in display characteristics of the light emitting display device being affected.